Proper Psalms i.e. psalms adapted by their contents to the subjects of particular Sundays or festivals and holydays. St. Chrysostom refers to ancient prescription in this matter, and St. Augustine mentions as an old custom the use of Psalm 22 on Good Friday. Cassian informs us that Psalm 63 was sung at matins, and the 141st at evensong. St. Athanasius and St. Augustine appointed special psalms on certain occasions.